ofPyroxylic Spiril, and of its derived Combinations, 47 



was obtained quite free from atmosphoric air by having been 

 boiled for a long time, and then allowed to cool in closely 

 stoppered vessels. A quantity of this solution was placed in a 

 small retort, with which was connected a long tube containing 

 fragments of chloride of calcium, to the other extremity of 

 which was attached a tube containing black oxide of coj)})er, 

 and standing in connexion with the ordinary apparatus of 

 Liebig for absorbing the products of the combustion. The 

 tube with oxide of copper liaving been carried to a dull red 

 heat, the retort was warmed until it began to give out pretty 

 copiously the gaseous methylic aLther, which streaming over 

 the red hot oxide of copper gave water and carbonic acid. 

 The process was continued until there were obtained : 



Water generated by the combustion = 1'286 gramme. 



Carbonic acid 2*071 



giving ^ 



Hydrogen 1411 1000 rr., 1000 6H 



^ -^ , ^ ~ •=. = . 1 heory = — p_ 



Carbon 5726 4058 ^ 4083 2 C • 



The ratio of the carbon and hydrogen is the same as in al- 

 cohol, and as given by Dumas and Peligot; and as the atomic 

 weight has been accurately determined by the analysis of the 

 sulpho-methylates by Dumas and by myself, the basis of the 

 methylene series is put beyond the possibility of doubt. 



I have considered this confirmation of Dumas's view of 

 the methylene alcohol and aether sufficiently important to be 

 brought forward, and shall now pass to the examination of 

 some results to which the French chemists did not attend. 



Of the Compowid of Chloride of Calcium with Pyroxylic 

 Spirit. — This body, to which allusion has been already made, 

 crystallizes readily in large six-sided tables (rhomboidal): ex- 

 posed to the air it rapidly deliquesces, absorbing water, and 

 pyroxylic spirit becoming free, but over sulphuric acid the 

 crystals can be obtained completely dry. The analysis was 

 made simply by rapidly weighing a portion in a platinum 

 crucible, heating it gradually until all pyroxylic spirit was 

 driven off, and then fusing and weighing the residual chloride 

 of calcium. The result was as follows : 



Pyroxylic spirit... = 3*168 : 53*3, or 2 atoms = 5^'5QS 



Chloride of calcium 2*776 : 46*7, or 1 atom 46*435 



Grammes 5*944 100*0 100*000 



It therefore corresponds to the alcoholates [alcoates] ex- 

 amined by Graham*. 



Of the Oil which accompatiies Pyroxylic Spirit. — In the 



* [Mr. Giiham's paper on the Alcoates was reprinted in Phil. Mag. and 

 Annals, vol. iv. p. 265.— Edit.] 



